Ethernet in the first mile

Ethernet in the first mile (EFM) refers to using one of the Ethernet family of computer network protocols between a telecommunications company and a customer's premises. From the customer's point of view it is their "first" mile, although from the access network's point of view it is known as the "last mile". A working group of the Institute of Electrical and Electronics Engineers (IEEE) produced the standards known as IEEE 802.3ah-2004, which were later included in the overall standard IEEE 802.3-2008. Although it is often used for businesses, it can also be known as Ethernet to the Home (ETTH). One family of standards known as EPON uses a passive optical network.

One early effort was the EtherLoop technology invented at Nortel Networks in 1996, and then spun off into the company Elastic Networks in 1998.[1][2] Its principal inventor was Jack Terry. The hope was to combine the packet-based nature of Ethernet with the ability of Digital Subscriber Line (DSL) technology to work over existing telephone access wires.[3] The name comes from local loop, which traditionally describes the wires from a telephone company office to a subscriber. The protocol was half-duplex with control from the provider side of the loop. It adapted to line conditions with a peak of 10 Mbit/s advertised, but 4-6 Mbit/s more typical, at a distance of about 12,000 feet (3,700 m). Symbol rates were 1 megabaud or 1.67 megabaud, with 2, 4, or 6 bits per symbol.[1] The EtherLoop product name was registered as a trademark in the US and Canada.[4] The EtherLoop technology was eventually purchased by Paradyne Networks in 2002,[5] which was in turn purchased by Zhone Technologies in 2005.[6]

In October 2000 Howard Frazier issued a call for interest on "Ethernet in the Last Mile".[14] At the November 2000 meeting, IEEE 802.3 created the "Ethernet in the First Mile" study group, and on July 16, 2001 the 802.3ah working group. In parallel participating vendors formed the Ethernet in the First Mile Alliance (EFMA) in December 2001 to promote Ethernet subscriber access technology and support the IEEE standard efforts.[15] At an early meeting, the EtherLoop technology was called 100BASE-CU and another technology called EoVDSL for Ethernet over VDSL.[16]

The working group's EFM standard was approved on June 24, 2004 and published on September 7, 2004 as IEEE 802.3ah-2004. In 2005 it was included into the base IEEE 802.3 standard. In 2005, the EFMA was absorbed by the Metro Ethernet Forum.[17]

In early 2006, work began on an even higher-speed 10 gigabit/second Ethernet passive optical network (10G-EPON) standard, ratified in 2009 as IEEE 802.3av.[18] The work on the EPON was continued by the IEEE P802.3bk Extended EPON Task Force,[19] formed in March 2012. The major goals for this Task Force included adding support for PX30, PX40, PRX40, and PR40 power budget classes to both 1G-EPON and 10G-EPON. The 802.3bk amendment was approved by the IEEE-SA SB in August 2013 and published soon thereafter as the standard IEEE Std 802.3bk-2013.[20]

EFM also addresses other issues, required for mass deployment of Ethernet services, such as operations, administration, and management (OA&M)[22] and compatibility with existing technologies (such as plain old telephone service spectral compatibility for copper twisted pair).

Unlike 10BASE-T, 100BASE-T and 1000BASE-T PHYs, providing a single rate of 10, 100, or 1000 Mbit/s respectively, 2BASE-TL link rate can vary, depending on the copper media characteristics (such as length, wire diameter or gauge, number of pairs if the link is aggregated, amount of crosstalk between the pairs, etc.), desired link parameters (such as desired SNR margin, Power Back-Off, etc.), and regional spectral limitations.

2BASE-TL PHYs deliver a minimum of 2 Mbit/s over distances of up to 2.7 kilometres (8,900 ft), using ITU-TG.991.2 (G.SHDSL.bis) technology over a single copper pair. These PHYs may also support an optional aggregation or bonding of multiple copper pairs, called PME Aggregation Function (PAF).

For a single pair, the minimum possible link bitrate is 192 kbit/s (3 x 64 kbit/s) and the maximum bitrate is 5.7 Mbit/s (89 x 64 kbit/s). On a 0.5 mm wire with 3 dB noise margin and no spectral limitations, the max bitrate can be achieved over distances of up to 1 kilometre (3,300 ft). At 6 kilometres (20,000 ft) the max achievable bitrate is about 850 kbit/s.

The throughput of a 2BASE-TL link is lower than the link's bitrate by an average 5%, due to 64/65-octet encoding and PAF overhead, both factors depend on packet size.[26]

10PASS-TS PHYs deliver a minimum of 10 Mbit/s over distances of up to 750 metres (2,460 ft), using ITU-TG.993.1 (VDSL) technology over a single copper pair. These PHYs may also support an optional aggregation or bonding of multiple copper pairs, called PME Aggregation Function (PAF).

Unlike other Ethernet physical layers that provide a single rate such as 10, 100, or 1000 Mbit/s, 10PASS-TS link rate can vary, similar to 2BASE-TL, depending on the copper channel characteristics, such as length, wire diameter (gauge), wiring quality, the number of pairs if the link is aggregated and other factors.

VDSL is a short range technology designed to provide broadband over distances less than 1 km of voice-grade coppertwisted pair line, but connection data rates deteriorate quickly as the line distance increases. This has led to VDSL being referred to as a "fiber to the curb" technology, because it requires fiber backhaul to connect with a carrier network over greater distances.

VDSL Ethernet in the first mile services using may be a useful way to standardise functionality on Metro Ethernet networks, or potentially to distribute internet access services over voice-grade wiring in multi-dwelling unit buildings. However, VDSL2 has already proven to be a versatile and faster standard with greater reach than VDSL.

1.
Ethernet
–
Ethernet /ˈiːθərnɛt/ is a family of computer networking technologies commonly used in local area networks, metropolitan area networks and wide area networks. It was commercially introduced in 1980 and first standardized in 1983 as IEEE802.3, over time, Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a medium, while the newer Ethernet variants use twisted pair. Over the course of its history, Ethernet data transfer rates have increased from the original 2.94 megabits per second to the latest 100 gigabits per second. The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet, systems communicating over Ethernet divide a stream of data into shorter pieces called frames. As per the OSI model, Ethernet provides services up to, since its commercial release, Ethernet has retained a good degree of backward compatibility. Features such as the 48-bit MAC address and Ethernet frame format have influenced other networking protocols, the primary alternative for some uses of contemporary LANs is Wi-Fi, a wireless protocol standardized as IEEE802.11. Ethernet was developed at Xerox PARC between 1973 and 1974 and it was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, in 1976, after the system was deployed at PARC, Metcalfe and Boggs published a seminal paper. Metcalfe left Xerox in June 1979 to form 3Com and he convinced Digital Equipment Corporation, Intel, and Xerox to work together to promote Ethernet as a standard. The so-called DIX standard, for Digital/Intel/Xerox, specified 10 Mbit/s Ethernet, with 48-bit destination and source addresses and it was published on September 30,1980 as The Ethernet, A Local Area Network. Data Link Layer and Physical Layer Specifications, version 2 was published in November,1982 and defines what has become known as Ethernet II. Formal standardization efforts proceeded at the time and resulted in the publication of IEEE802.3 on June 23,1983. Ethernet initially competed with two largely proprietary systems, Token Ring and Token Bus, in the process, 3Com became a major company. 3Com shipped its first 10 Mbit/s Ethernet 3C100 NIC in March 1981, an Ethernet adapter card for the IBM PC was released in 1982, and, by 1985, 3Com had sold 100,000. Parallel port based Ethernet adapters were produced for a time, with drivers for DOS, by the early 1990s, Ethernet became so prevalent that it was a must-have feature for modern computers, and Ethernet ports began to appear on some PCs and most workstations. This process was sped up with the introduction of 10BASE-T and its relatively small modular connector. Since then, Ethernet technology has evolved to meet new bandwidth, in addition to computers, Ethernet is now used to interconnect appliances and other personal devices

2.
Computer network
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A computer network or data network is a telecommunications network which allows nodes to share resources. In computer networks, networked computing devices exchange data with other using a data link. The connections between nodes are established using either cable media or wireless media, the best-known computer network is the Internet. Network computer devices that originate, route and terminate the data are called network nodes, nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices can be said to be networked together when one device is able to exchange information with the other device, Computer networks differ in the transmission medium used to carry their signals, communications protocols to organize network traffic, the networks size, topology and organizational intent. In most cases, application-specific communications protocols are layered over other more general communications protocols and this formidable collection of information technology requires skilled network management to keep it all running reliably. The chronology of significant computer-network developments includes, In the late 1950s, in 1960, the commercial airline reservation system semi-automatic business research environment went online with two connected mainframes. Licklider developed a group he called the Intergalactic Computer Network. In 1964, researchers at Dartmouth College developed the Dartmouth Time Sharing System for distributed users of computer systems. The same year, at Massachusetts Institute of Technology, a group supported by General Electric and Bell Labs used a computer to route. Throughout the 1960s, Leonard Kleinrock, Paul Baran, and Donald Davies independently developed network systems that used packets to transfer information between computers over a network, in 1965, Thomas Marill and Lawrence G. Roberts created the first wide area network. This was an precursor to the ARPANET, of which Roberts became program manager. Also in 1965, Western Electric introduced the first widely used telephone switch that implemented true computer control, in 1972, commercial services using X.25 were deployed, and later used as an underlying infrastructure for expanding TCP/IP networks. In July 1976, Robert Metcalfe and David Boggs published their paper Ethernet, Distributed Packet Switching for Local Computer Networks, in 1979, Robert Metcalfe pursued making Ethernet an open standard. In 1976, John Murphy of Datapoint Corporation created ARCNET, a network first used to share storage devices. In 1995, the transmission speed capacity for Ethernet increased from 10 Mbit/s to 100 Mbit/s, by 1998, Ethernet supported transmission speeds of a Gigabit. Subsequently, higher speeds of up to 100 Gbit/s were added, the ability of Ethernet to scale easily is a contributing factor to its continued use. Providing access to information on shared storage devices is an important feature of many networks, a network allows sharing of files, data, and other types of information giving authorized users the ability to access information stored on other computers on the network

3.
Access network
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An access network is a type of telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the network, which connects local providers to each other. The access network may be divided between feeder plant or distribution network, and drop plant or edge network. An access network or outside plant refers to the series of wires, cables, the local exchange contains banks of automated switching equipment to direct a call or connection to the consumer. The access network is one of the oldest assets a telecoms operator owns, and is constantly evolving, growing as new customers are connected. This makes the network one of the most complex networks in the world to maintain. In 2007–2008 many telecommunication operators experienced increasing problems maintaining the quality of the records which describe the network, in 2006, according to an independent Yankee Group report, globally operators experience profit leakage in excess of €15 Billion each year. The access network is perhaps the most valuable asset an operator owns. Access networks consist largely of pairs of wires, each traveling in a direct path between the exchange and the customer. In some instances, these wires may even be aluminum, the use of which was common in the 1960s and 1970s following an increase in the cost of copper. As it happened, the increase was temporary, but the effect of this decision is still felt today because the aluminum wires oxidize. Operators offered additional services such as xDSL based broadband and IPTV to guarantee profit, the access network is again the main barrier to achieving these profits since operators worldwide have accurate records of only 40% to 60% of the network. Access networks around the world evolved to more and more optical fiber technology. The process of communicating with a network begins with an access attempt, an access attempt itself begins with an issuance of an access request by an access originator. Access failure can be the result of access outage, user blocking, incorrect access, Access denial can include, Access failure caused by the issuing of a system blocking signal by a communications system that does not have a call-originator camp-on feature. Access failure caused by exceeding the maximum time and nominal system access time fraction during an access attempt. Although some access charges are billed directly to interexchange carriers, a significant percentage of all charges are paid by the local end users. Faster PON standards generally support a split ratio of users per PON

4.
Last mile
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More specifically, the last mile refers to the portion of the telecommunications network chain that physically reaches the end-users premises. The word mile is used metaphorically, the length of the last mile link may be more or less than a mile. Because the last mile of a network to the user is conversely the first mile from the premises to the outside world when the user is sending data. The last mile is typically the speed bottleneck in communication networks and this is because retail telecommunication networks have the topology of trees, with relatively few high capacity trunk communication channels branching out to feed many final mile leaves. To resolve, or at least mitigate, the problems involved with attempting to provide enhanced services over the last mile, one example is fixed wireless access, where a wireless network is used instead of wires to connect a stationary terminal to the wireline network. Various solutions are being developed which are seen as an alternative to the last mile of standard incumbent local exchange carriers and these include WiMAX and broadband over power lines. This ISDN30 can carry 30 simultaneous telephone calls and many direct dial telephone numbers, when leaving the telephone exchange, the ISDN30 cable can be buried in the ground, usually in ducting, at very little depth. Loss, therefore, of the last mile link, means the non-delivery of calls, any business with ISDN30 type connectivity must anticipate such failure in its business continuity planning. There are many options, as documented in customer proprietary network information, if the cable is damaged from one telephone exchange to the customer premises most of the calls can be delivered from the surviving route to the customer. Diverse routing is where the carrier can provide more than one route to supply ISDN30 connectivity from the exchange, or exchanges, carrier diversions are usually limited to all of the ISDN30 direct dial telephone numbers being delivered to one single number. Carrier diversions are usually limited to all of the ISDN30 direct dial telephone numbers being delivered to one single number, in the UK Teamphone offers this service in association with British Telecom. By not being in the exchanges, the Teamphone version offers an all or nothing diversion service if required and these are generally carrier-independent and there are a number of companies offering such solutions in the UK and AirNorth Communications in the United States. Hosted numbers is where the carriers or specialist companies can host the customers numbers within their own or the carriers networks, when a diversion service is required, the calls can be routed to alternative numbers. Both carriers and specialist companies offer this type of service in the UK, as demand has escalated, particularly fueled by the widespread adoption of the Internet, the need for economical high-speed access by end-users located at millions of locations has ballooned as well. As requirements have changed, the systems and networks that were initially pressed into service for this purpose have proven to be inadequate. To date, although a number of approaches have been tried, since the integral of the rate of information transfer with respect to time is information quantity, this requirement leads to a corresponding minimum energy per bit. The problem of sending any given amount of information across a channel can therefore be viewed in terms of sending sufficient Information-Carrying Energy, for this reason the concept of an ICE pipe or conduit is relevant and useful for examining existing systems. The distribution of information to a number of widely separated end-users can be compared to the distribution of many other resources

5.
Institute of Electrical and Electronics Engineers
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The Institute of Electrical and Electronics Engineers is a professional association with its corporate office in New York City and its operations center in Piscataway, New Jersey. It was formed in 1963 from the amalgamation of the American Institute of Electrical Engineers, today, it is the worlds largest association of technical professionals with more than 400,000 members in chapters around the world. Its objectives are the educational and technical advancement of electrical and electronic engineering, telecommunications, computer engineering, IEEE stands for the Institute of Electrical and Electronics Engineers. The association is chartered under this full legal name, IEEEs membership has long been composed of engineers and scientists. For this reason the organization no longer goes by the name, except on legal business documents. The IEEE is dedicated to advancing technological innovation and excellence and it has about 430,000 members in about 160 countries, slightly less than half of whom reside in the United States. The major interests of the AIEE were wire communications and light, the IRE concerned mostly radio engineering, and was formed from two smaller organizations, the Society of Wireless and Telegraph Engineers and the Wireless Institute. After World War II, the two became increasingly competitive, and in 1961, the leadership of both the IRE and the AIEE resolved to consolidate the two organizations. The two organizations merged as the IEEE on January 1,1963. The IEEE is incorporated under the Not-for-Profit Corporation Law of the state of New York and it was formed in 1963 by the merger of the Institute of Radio Engineers and the American Institute of Electrical Engineers. The IEEE serves as a publisher of scientific journals and organizer of conferences, workshops. IEEE develops and participates in activities such as accreditation of electrical engineering programs in institutes of higher learning. The IEEE logo is a design which illustrates the right hand grip rule embedded in Benjamin Franklins kite. IEEE has a dual complementary regional and technical structure – with organizational units based on geography and it manages a separate organizational unit which recommends policies and implements programs specifically intended to benefit the members, the profession and the public in the United States. The IEEE includes 39 technical Societies, organized around specialized technical fields, the IEEE Standards Association is in charge of the standardization activities of the IEEE. The IEEE History Center became an organization to the Engineering. The new ETHW is an effort by various engineering societies as a formal repository of topic articles, oral histories, first-hand histories, Landmarks + Milestones. The IEEE History Center is annexed to Stevens University Hoboken, NJ, in 2016, the IEEE acquired GlobalSpec, adding the provision of engineering data for a profit to its organizational portfolio

6.
Passive optical network
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A PON consists of an optical line terminal at the service providers central office and a number of optical network units or optical network terminals, near end users. A PON reduces the amount of fiber and central office equipment required compared with point-to-point architectures, a passive optical network is a form of fiber-optic access network. In most cases, downstream signals are broadcast to all premises sharing multiple fibers, upstream signals are combined using a multiple access protocol, usually time division multiple access. The Society of Cable Telecommunications Engineers also specified radio frequency over glass for carrying signals over an optical network. Starting in 1995, work on fiber to the home architectures was done by the Full Service Access Network working group, formed by major telecommunications service providers, the International Telecommunications Union did further work, and standardized on two generations of PON. The older ITU-T G.983 standard was based on Asynchronous Transfer Mode, a typical APON/BPON provides 622 megabits per second of downstream bandwidth and 155 Mbit/s of upstream traffic, although the standard accommodates higher rates. The ITU-T G. Again, the standards permit several choices of bit rate, but the industry has converged on 2.488 gigabits per second of downstream bandwidth, GPON Encapsulation Method allows very efficient packaging of user traffic with frame segmentation. By mid-2008, Verizon had installed over 800,000 lines, british Telecom, BSNL, Saudi Telecom Company, Etisalat, and AT&T were in advanced trials in Britain, India, Saudi Arabia, the UAE, and the USA, respectively. GPON networks have now been deployed in numerous networks across the globe, G.987 defined 10G-PON with 10 Gbit/s downstream and 2.5 Gbit/s upstream – framing is G-PON like and designed to coexist with GPON devices on the same network. The chief information officer of the United States Department of the Army issued a directive to adopt the technology by fiscal year 2013 and it is marketed to the US military by companies such as Telos Corporation. In 2004, the Ethernet PON standard 802. 3ah-2004 was ratified as part of the Ethernet in the first mile project of the IEEE802.3, EPON uses standard 802.3 Ethernet frames with symmetric 1 gigabit per second upstream and downstream rates. EPON is applicable for data-centric networks, as well as voice, data. 10 Gbit/s EPON or 10G-EPON was ratified as an amendment IEEE802. 3av to IEEE802.3, the upstream channel can support simultaneous operation of IEEE802. 3av and 1 Gbit/s 802. 3ah simultaneously on a single shared channel. There are currently over 40 million installed EPON ports making it the most widely deployed PON technology globally, EPON is also the foundation for cable operators’ business services as part of the DOCSIS Provisioning of EPON specifications. A PON takes advantage of wavelength division multiplexing, using one wavelength for downstream traffic, BPON, EPON, GEPON, and GPON have the same basic wavelength plan and use the 1490 nanometer wavelength for downstream traffic and 1310 nm wavelength for upstream traffic. 1550 nm is reserved for optional overlay services, typically RF video, as with bit rate, the standards describe several optical budgets, most common is 28 dB of loss budget for both BPON and GPON, but products have been announced using less expensive optics as well. 28 dB corresponds to about 20 km with a 32-way split, forward error correction may provide for another 2–3 dB of loss budget on GPON systems. As optics improve, the 28 dB budget will likely increase, although both the GPON and EPON protocols permit large split ratios, in practice most PONs are deployed with a split ratio of 1,32 or smaller

7.
Wide area network
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A wide area network is a telecommunications network or computer network that extends over a large geographical distance. Wide area networks are often established with leased telecommunication circuits, business, education and government entities use wide area networks to relay data among staff, students, clients, buyers, and suppliers from various locations across the world. In essence, this mode of telecommunication allows a business to carry out its daily function regardless of location. The Internet may be considered a WAN, the textbook definition of a WAN is a computer network spanning regions, countries, or even the world. WANs do not just necessarily connect physically disparate LANs, a CAN, for example, may have a localised backbone of a WAN technology, which connects different LANs within a campus. This could be to facilitate higher bandwidth applications, or provide better functionality for users in the CAN, WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private, others, built by Internet service providers, provide connections from an organizations LAN to the Internet. WANs are often built using leased lines, at each end of the leased line, a router connects the LAN on one side with a second router within the LAN on the other. Leased lines can be very expensive, instead of using leased lines, WANs can also be built using less costly circuit switching or packet switching methods. Network protocols including TCP/IP deliver transport and addressing functions, protocols including Packet over SONET/SDH, Multiprotocol Label Switching, Asynchronous Transfer Mode and Frame Relay are often used by service providers to deliver the links that are used in WANs. X.25 was an important early WAN protocol, and is considered to be the grandfather of Frame Relay as many of the underlying protocols. Academic research into wide area networks can be broken down into three areas, mathematical models, network emulation and network simulation, performance improvements are sometimes delivered via wide area file services or WAN optimization. Many technologies are available for wide area network links, examples include circuit switched telephone lines, radio wave transmission, and optic fiber. New developments in technologies have successively increased transmission rates,1960, a 110 bit/s line was normal on the edge of the WAN, while core links of 56 kbit/s to 64 kbit/s were considered fast. AT&T plans to start conducting trials in the year 2017 for businesses to use 400 Gigabit Ethernet, researchers Robert Maher, Alex Alvarado, Domaniç Lavery & Polina Bayvel of University College London were able to increase networking speeds to 1.125 Terabits per second. Christos Santis, graduate student Scott Steger, Amnon Yariv, Martin, ATM Cable modem Dial-up DSL Frame relay ISDN Leased line SONET X.25 SD-WAN Cisco - Introduction to WAN Technologies

8.
Local area network
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By contrast, a wide area network, not only covers a larger geographic distance, but also generally involves leased telecommunication circuits or Internet links. An even greater contrast is the Internet, which is a system of globally connected business, Ethernet and Wi-Fi are the two most common transmission technologies in use for local area networks. Historical technologies include ARCNET, Token ring, and AppleTalk, the increasing demand and use of computers in universities and research labs in the late 1960s generated the need to provide high-speed interconnections between computer systems. A1970 report from the Lawrence Radiation Laboratory detailing the growth of their Octopus network gave an indication of the situation. A number of experimental and early commercial LAN technologies were developed in the 1970s, Cambridge Ring was developed at Cambridge University starting in 1974. Ethernet was developed at Xerox PARC in 1973–1975, and filed as U. S, in 1976, after the system was deployed at PARC, Robert Metcalfe and David Boggs published a seminal paper, Ethernet, Distributed Packet-Switching for Local Computer Networks. ARCNET was developed by Datapoint Corporation in 1976 and announced in 1977 and it had the first commercial installation in December 1977 at Chase Manhattan Bank in New York. The initial driving force for networking was generally to share storage and printers, there was much enthusiasm for the concept and for several years, from about 1983 onward, computer industry pundits would regularly declare the coming year to be, “The year of the LAN”. In practice, the concept was marred by proliferation of incompatible physical layer and network protocol implementations, typically, each vendor would have its own type of network card, cabling, protocol, and network operating system. Netware dominated the personal computer LAN business from early after its introduction in 1983 until the mid-1990s when Microsoft introduced Windows NT Advanced Server, of the competitors to NetWare, only Banyan Vines had comparable technical strengths, but Banyan never gained a secure base. During the same period, Unix workstations were using TCP/IP networking, early LAN cabling had generally been based on various grades of coaxial cable. This led to the development of 10BASE-T and structured cabling which is still the basis of most commercial LANs today, while fiber-optic cabling is common for links between switches, use of fiber to the desktop is rare. Many LANs use wireless technologies that are built into Smartphones, tablet computers, in a wireless local area network, users may move unrestricted in the coverage area. Wireless networks have become popular in residences and small businesses, because of their ease of installation, guests are often offered Internet access via a hotspot service. Network topology describes the layout of interconnections between devices and network segments, at the data link layer and physical layer, a wide variety of LAN topologies have been used, including ring, bus, mesh and star. At the higher layers, NetBEUI, IPX/SPX, AppleTalk and others were once common, simple LANs generally consist of cabling and one or more switches. A switch can be connected to a router, cable modem, a LAN can include a wide variety of other network devices such as firewalls, load balancers, and network intrusion detection. LANs can maintain connections with other LANs via leased lines, leased services, depending on how the connections are established and secured, and the distance involved, such linked LANs may also be classified as a metropolitan area network or a wide area network

9.
Asynchronous Transfer Mode
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ATM was developed to meet the needs of the Broadband Integrated Services Digital Network, as defined in the late 1980s, and designed to unify telecommunication and computer networks. It was designed for a network that must handle both traditional high-throughput data traffic, and real-time, low-latency content such as voice and video. The reference model for ATM approximately maps to the three lowest layers of the ISO-OSI reference model, network layer, data link layer, and physical layer. ATM is a protocol used over the SONET/SDH backbone of the public switched telephone network and Integrated Services Digital Network. This differs from approaches such as the Internet Protocol or Ethernet that use variable sized packets, ATM uses a connection-oriented model in which a virtual circuit must be established between two endpoints before the actual data exchange begins. ATM eventually became dominated by Internet Protocol only technology, in the ISO-OSI reference model data link layer, the basic transfer units are generically called frames. In ATM these frames are of a length and specifically called cells. Under normal queuing conditions the cells might experience maximum queuing delays, to avoid this issue, all ATM packets, or cells, are the same small size. In addition, the cell structure means that ATM can be readily switched by hardware without the inherent delays introduced by software switched and routed frames. Thus, the designers of ATM utilized small data cells to reduce jitter in the multiplexing of data streams.544 to 45 Mbit/s in the USA, at this rate, a typical full-length 1500 byte data packet would take 77.42 µs to transmit. In a lower-speed link, such as a 1.544 Mbit/s T1 line, a queuing delay induced by several such data packets might exceed the figure of 7.8 ms several times over, in addition to any packet generation delay in the shorter speech packet. This was clearly unacceptable for speech traffic, which needs to have low jitter in the stream being fed into the codec if it is to produce good-quality sound. This allows smoothing out the jitter, but the delay introduced by passage through the buffer would require echo cancellers even in local networks, also, it would have increased the delay across the channel, and conversation is difficult over high-delay channels. Build a system that can provide low jitter to traffic that needs it. Operate on a 1,1 user basis, the design of ATM aimed for a low-jitter network interface. However, cells were introduced into the design to provide short queuing delays while continuing to support datagram traffic, ATM broke up all packets, data, and voice streams into 48-byte chunks, adding a 5-byte routing header to each one so that they could be reassembled later. The choice of 48 bytes was political rather than technical, most of the European parties eventually came around to the arguments made by the Americans, but France and a few others held out for a shorter cell length. With 32 bytes, France would have been able to implement an ATM-based voice network with calls from one end of France to the other requiring no echo cancellation,48 bytes was chosen as a compromise between the two sides

10.
Nortel
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It was founded in Montreal, Quebec in 1895 as the Northern Electric and Manufacturing Company. At its height, Nortel accounted for more than a third of the valuation of all the companies listed on the Toronto Stock Exchange. Nortel had filed for protection from its creditors in the United States, Canada, in June 2009, the company announced it would cease operations and sell off all of its business units. The period of protection was extended to February 2,2013. As part of the proceedings in the United States, Nortel Networks Inc. publishes monthly operating reports outlining cash receipts and disbursements. By 2016 Nortel had sold billions of dollars worth of assets and he later refined its design at Brantford after producing his first working prototype in Boston. In addition to phones, four years later, the department started manufacturing its first switchboard, the small manufacturing department expanded yearly with the growth and popularity of the telephone to 50 employees in 1888. By 1890 it had transformed into its own branch of operations with 200 employees. As the manufacturing branch expanded, its production ability increased beyond the demand for phones and this was a problem because the Bell Telephone Company of Canadas charter would not allow them to build other products. This company was incorporated as the Northern Electric and Manufacturing Company Limited, Northern Electric and Manufacturing Company Limited was incorporated on 7 December 1895, by the following corporate members, Charles Fleetford Sise Sr. McFarlane, manager, all of the city and district of Montreal, the initial stock capital was $50,000 at $100 per share, with 93 percent held by the Bell Telephone Company of Canada and the remainder held by the seven corporate members above. The first general meeting was held on March 24,1896. In December 1899, The Bell Telephone Company of Canada bought a company for $500,000. Northern Electric and Manufacturing further expanded its line in 1900. In 1911 the Wire and Cable company changed its name to the Imperial Wire, the construction of a new manufacturing plant started in 1913 at Shearer Street in Montreal, Canada, as preparations began for the two manufacturing companies integration. This facility at Shearer Street was the manufacturing centre until the mid-1950s. Edward Fleetford Sise was the president and his brother Paul Fleetford Sise was the vice-president, during the First World War Northern Electric manufactured the Portable Commutator, a one-wire telegraphic switchboard for military operations in the field. In 1922, Northern started to produce, for $5, the Peanut vacuum tube, the use of alternating current was still under development during this time

11.
Digital Subscriber Line
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Digital subscriber line is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line, DSL service can be delivered simultaneously with wired telephone service on the same telephone line. This is possible because DSL uses higher frequency bands for data, on the customer premises, a DSL filter on each non-DSL outlet blocks any high-frequency interference to enable simultaneous use of the voice and DSL services. Bit rates of 1 Gbit/s have been reached in trials, in ADSL, the data throughput in the upstream direction is lower, hence the designation of asymmetric service. In symmetric digital subscriber line services, the downstream and upstream data rates are equal, researchers at Bell Labs have reached speeds of 10 Gbit/s, while delivering 1 Gbit/s symmetrical broadband access services using traditional copper telephone lines. These higher speeds are lab results, however, a 2012 survey found that DSL continues to be the dominant technology for broadband access with 364.1 million subscribers worldwide. For a long time it was thought that it was not possible to operate a conventional phone-line beyond low-speed limits, in the 1950s, ordinary twisted-pair telephone-cable often carried four megahertz television signals between studios, suggesting that such lines would allow transmitting many megabits per second. One such circuit in the UK ran some ten miles between the BBC studios in Newcastle-upon-Tyne and the Pontop Pike transmitting station and it was able to give the studios a low quality cue feed but not one suitable for transmission. However, these cables had other impairments besides Gaussian noise, preventing such rates from becoming practical in the field, the 1980s saw the development of techniques for broadband communications that allowed the limit to be greatly extended. A patent was filed in 1979 for the use of existing telephone wires for both telephones and data terminals that were connected to a computer via a digital data carrier system. Joseph W. Lechleiders contribution to DSL was his insight that an asymmetric arrangement offered more than double the capacity of symmetric DSL. ADSL supports two modes of transport—fast channel and interleaved channel, fast channel is preferred for streaming multimedia, where an occasional dropped bit is acceptable, but lags are less so. Interleaved channel works better for file transfers, where the data must be error-free. Older ADSL standards delivered 8 Mbit/s to the customer over about 2 km of unshielded twisted-pair copper wire, distances greater than 2 km significantly reduce the bandwidth usable on the wires, thus reducing the data rate. But ADSL loop extenders increase these distances by repeating the signal, until the late 1990s, the cost of digital signal processors for DSL was prohibitive. All types of DSL employ highly complex digital signal processing algorithms to overcome the inherent limitations of the twisted pair wires. Due to the advancements of very-large-scale integration technology, the cost of the equipment associated with a DSL deployment lowered significantly, the two main pieces of equipment are a digital subscriber line access multiplexer at one end and a DSL modem at the other end. A DSL connection can be deployed over existing cable, such deployment, even including equipment, is much cheaper than installing a new, high-bandwidth fiber-optic cable over the same route and distance

12.
Half-duplex
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A duplex communication system requires a pair of channels/frequencies hence the term duplex meaning two parts. The two channels are defined as uplink/downlink or reverse/forward, in a full-duplex system simultaneous transmission/reception is available, i. e. One can transmit and receive simultaneously, in a half-duplex system, each party can communicate with the other but not simultaneously, the communication is one direction at a time. Half duplex systems utilize separate channels for uplink and downlink, i. e. a transmit, in a half duplex communications system one user is allowed to transmit on the uplink channel at a time. The transmitted uplink signal is frequency translated via a radio/repeater to the downlink receive frequency which is received by all other radios tuned to the downlink/receive frequency. A half-duplex system is defined as system which operates two, hence duplex, dedicated uplink/downlink channels/frequencies. In a half duplex system a single path is provided for uplink, all uplink messages are broadcast via the downlink channel to all users simultaneously via a repeater which performs uplink to downlink channel/frequency translation. All cellular and land line PSTNs and PDSNs are full duplex systems, all full duplex systems require a channel/frequency translator via a radio/repeater. This is required in order to translate the uplink/transmit transmission from one to the downlink/receive channel/frequency of user two. Full duplex systems are one to one private systems unlike half duplex systems which broadcast to all users and this effectively makes the cable itself a collision-free environment and doubles the maximum total transmission capacity supported by each Ethernet connection. Time-division duplexing is commonly referred to as simplex communications, a single channel/frequency is employed for bidirectional communications. The term simplex communication as applied to TDM single channel systems predates the term TDD by at least 80 years, frequency-division duplexing as with any other duplex system is defined by two channel/frequency simultaneous communication. A channel/frequency pair are assigned to individual user on the system. An FDD system requires frequency translation from user 1 uplink/reverse frequency to user 2 downlink/forward frequency, full-duplex audio systems like telephones can create echo, which needs to be removed. Echo occurs when the coming out of the speaker, originating from the far end. The sound then reappears at the source end, but delayed. This feedback path may be acoustic, through the air, or it may be mechanically coupled, echo cancellation is a signal-processing operation that subtracts the far-end signal from the microphone signal before it is sent back over the network. Echo cancellation is important to the V.32, V.34, V.56, echo cancelers are available as both software and hardware implementations

13.
Fiber optic communication
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Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms a carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals. Researchers at Bell Labs have reached speeds of over 100 petabit×kilometer per second using fiber-optic communication. First developed in the 1970s, fiber-optics have revolutionized the industry and have played a major role in the advent of the Information Age. Because of its advantages over electrical transmission, optical fibers have largely replaced copper wire communications in core networks in the developed world, due to much lower attenuation and interference, optical fiber has large advantages over existing copper wire in long-distance and high-demand applications. However, infrastructure development within cities was difficult and time-consuming. Since 2000, the prices for fiber-optic communications have dropped considerably, the price for rolling out fiber to the home has currently become more cost-effective than that of rolling out a copper based network. Prices have dropped to $850 per subscriber in the US and lower in countries like The Netherlands, since 1990, when optical-amplification systems became commercially available, the telecommunications industry has laid a vast network of intercity and transoceanic fiber communication lines. Bell considered it his most important invention, the device allowed for the transmission of sound on a beam of light. On June 3,1880, Bell conducted the worlds first wireless transmission between two buildings, some 213 meters apart. Due to its use of a transmission medium, the Photophone would not prove practical until advances in laser. The Photophones first practical use came in military communication systems many decades later, in 1954 Harold Hopkins and Narinder Singh Kapany showed that rolled fiber glass allowed light to be transmitted. Initially it was considered that the light can traverse in only straight medium, after a period of research starting from 1975, the first commercial fiber-optic communications system was developed, which operated at a wavelength around 0.8 µm and used GaAs semiconductor lasers. This first-generation system operated at a bit rate of 45 Mbit/s with repeater spacing of up to 10 km, soon on 22 April 1977, General Telephone and Electronics sent the first live telephone traffic through fiber optics at a 6 Mbit/s throughput in Long Beach, California. The second generation of fiber-optic communication was developed for use in the early 1980s, operated at 1.3 µm. In 1984, they had developed a fiber optic cable that would help further their progress toward making fiber optic cables that would circle the globe. Canadian service provider SaskTel had completed construction of what was then the world’s longest commercial fiberoptic network, by 1987, these systems were operating at bit rates of up to 1.7 Gb/s with repeater spacing up to 50 km

14.
Fiber to the home
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Fiber to the x is a generic term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile telecommunications. As fiber optic cables are able to much more data than copper cables, especially over long distances. FTTX is a generalization for several configurations of fibre deployment, arranged into two groups, FTTP/FTTH/FTTB and FTTC/N, the telecommunications industry differentiates between several distinct FTTX configurations. The terms in most widespread use today are, FTTP, This term is used either as a term for both FTTH and FTTB, or where the fiber network includes both homes and small businesses. FTTH, Fiber reaches the boundary of the space, such as a box on the outside wall of a home. Passive optical networks and point-to-point Ethernet are architectures that deliver services over FTTH networks directly from an operators central office. FTTD, Fiber connection is installed from the computer room to a terminal or fiber media converter near the users desk. FTTO, Fiber connection is installed from the main computer room/core switch to a special mini-switch located at the user´s workstation or service points and this mini-switch provides Ethernet services to end user devices via standard twisted pair patch cords. The switches are located all over the building, but managed from one central point. FTTE and FTTZ are not considered part of the FTTX group of technologies, FTTF This is very similar to FTTB. In a fiber to the front yard scenario, each fiber node serves a single subscriber and this allows for multi-gigabit speeds using XG-fast technology. The fiber node may be reverse-powered by the subscriber modem, FTTN is often an interim step toward full FTTH and is typically used to deliver advanced triple-play telecommunications services. FTTC is occasionally ambiguously called FTTP, leading to confusion with the distinct fiber-to-the-premises system, the FTTH Councils do not have formal definitions for FTTC and FTTN. While fiber optic cables can carry data at speeds over long distances, copper cables used in traditional telephone lines. For example, the form of gigabit Ethernet runs over relatively economical category 5e, category 6 or augmented category 6 unshielded twisted-pair copper cabling. However,1 Gbit/s ethernet over fiber can easily reach tens of kilometres, therefore, FTTP has been selected by every major communications provider in the world to carry data over long 1 Gbit/s symmetrical connections directly to consumer homes. FTTP configurations that bring fiber directly into the building can offer the highest speeds since the segments can use standard ethernet or coaxial cable. Google Fiber provides speed of 1 Gbit/s, still, the type and length of employed fibers chosen, e. g. multimode vs. single-mode, are critical for applicability for future connections of over 1 Gbit/s

15.
Infineon Technologies
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As of 30 September 2016, Infineon had 36,299 employees worldwide. In fiscal year 2016, the company achieved sales of €6.473 billion, on 1 May 2006, Infineons Memory Products division was carved out as a distinct company called Qimonda AG, which at its height employed about 13,500 people worldwide. Qimonda was listed on the New York Stock Exchange until 2009, Infineon Technologies AG, in Neubiberg near Munich, offers semiconductors and systems for automotive, industrial, and multimarket sectors, as well as chipcard and security products. With a global presence, Infineon operates through its subsidiaries in the USA, from Milpitas, California, Infineon has a number of facilities in Europe, one in Dresden, Germany, Europes microelectronic, and emerging technologies center. Infineons high power segment is in Warstein, Germany, Villach and Graz in Austria, Cegléd in Hungary, and Italy. It also runs R&D centers in France, Singapore, Romania, Taiwan, UK and India, as well as units in Singapore, Malaysia, Indonesia. Theres also a Shared Service Center in Maia, Portugal, Infineon is listed in the DAX index of the Frankfurt Stock Exchange. After several restructurings, Infineon today comprises four areas, Infineon provides semiconductor products for use in powertrains. The product portfolio includes microcontrollers, power semiconductors and sensors, in fiscal year 2013, sales amounted to €1,714 million for the ATV segment. The industrial division of the company includes power semiconductors and modules which are used for generation, transmission and consumption of electrical energy and its application areas include control of electric drives for industrial applications and household appliances, modules for renewable energy production, conversion and transmission. This segment achieved sales of €651 million in fiscal year 2013, the division Power Management & Control sums up the business with semiconductor components for efficient power management or high-frequency applications. In fiscal year 2013 PMM generated €987 million, the CCS business provides microcontrollers for mobile phone SIM cards, payment cards, security chips and chip-based solutions for passports, identity cards and other official documents. Infineon delivers a significant number of chips for the new German identity card, in addition, CCS provides solutions for applications with high security requirements such as pay television and Trusted Computing. CCS achieved €463 million in fiscal year 2013, Infineon is the number 1 in embedded security. The former memory chip division was carved out in 2006 as Infineon’s subsidiary Qimonda, in January 2009, Qimonda filed for bankruptcy with the district court in Munich. On 7 July 2009, Infineon Technologies AG agreed by contract with the U. S. investor Golden Gate Capital on the sale of its Wireline Communications for €250 million, the resulting new company is now known as Lantiq. On 31 January 2011, the sale of the segment of wireless solutions to Intel was completed. The resulting new company has approximately 3,500 employees and now operates as Intel Mobile Communications, in July 2016, Infineon announced it agreed to buy the North Carolina-based company Wolfspeed from Cree Inc. for $850 million in cash

16.
Baseband
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Baseband is a signal that has a very narrow and near-zero frequency range, i. e. a spectral magnitude that is nonzero only for frequencies in the vicinity of the origin and negligible elsewhere. In telecommunications and signal processing, baseband signals are transmitted without modulation, baseband has a low-frequency—contained within the bandwidth frequency close to 0 hertz up to a higher cut-off frequency. Baseband can be synonymous with lowpass or non-modulated, and is differentiated from passband, bandpass, carrier-modulated, intermediate frequency, or radio frequency. A baseband bandwidth is equal to the highest frequency of a signal or system, or a bound on such frequencies. By contrast, passband bandwidth is the difference between a highest frequency and a nonzero lowest frequency, a baseband channel or lowpass channel is a communication channel that can transfer frequencies that are very near zero. Examples are serial cables and local networks, as opposed to passband channels such as radio frequency channels. Frequency division multiplexing allows an analog telephone wire to carry a telephone call. Passband transmission makes communication possible over a bandpass filtered channel, such as the telephone network local-loop or a wireless channel. The word BASE in Ethernet physical layer standards, for example 10BASE5, 100BASE-TX and 1000BASE-SX, a baseband processor also known as BP or BBP is used to process the down-converted digital signal to retrieve essential data for the wireless digital system. The baseband processing block in receivers is usually responsible for providing data, code pseudo-ranges and carrier phase measurements. A baseband signal or lowpass signal is a signal that can include frequencies that are very near zero, the equivalent baseband signal is Z = I + j Q where I is the inphase signal, Q the quadrature phase signal, and j the imaginary unit. In a digital method, the I and Q signals of each modulation symbol are evident from the constellation diagram. The frequency spectrum of this includes negative as well as positive frequencies. The physical passband signal corresponds to I cos ⁡ − Q sin ⁡ = R e where ω is the angular frequency in rad/s. A signal at baseband is often used to modulate a higher frequency signal in order that it may be transmitted via radio. Modulation results in shifting the signal up to higher frequencies than it originally spanned. A key consequence of the usual double-sideband amplitude modulation is that the range of frequencies the signal spans is doubled, thus, the RF bandwidth of a signal is twice its baseband bandwidth. Steps may be taken to reduce this effect, such as single-sideband modulation, some transmission schemes such as frequency modulation use even more bandwidth

17.
Passband
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A passband is the range of frequencies or wavelengths that can pass through a filter. For example, a radio receiver contains a filter to select the frequency of the desired radio signal out of all the radio waves picked up by its antenna. The passband of a receiver is the range of frequencies it can receive, a bandpass-filtered signal, is known as a bandpass signal, in contrast to a baseband signal. In telecommunications, optics, and acoustics, a passband is the portion of the spectrum that is transmitted by some filtering device. In other words, it is a band of frequencies which passes through some filter or set of filters, the accompanying figure shows a schematic of a waveform being filtered by a bandpass filter consisting of a highpass and a lowpass filter. Radio receivers generally include a tunable band-pass filter with a passband that is enough to accommodate the bandwidth of the radio signal transmitted by a single station. There are two categories of digital communication transmission methods, baseband and passband. In baseband transmission, line coding is utilized, resulting in a train or pulse amplitude modulated signal. This is typically used over non-filtered wires such as fiber optical cables and short-range copper links, for example, V.29, V.35, IEEE802.3, SONET/SDH. In passband transmission, digital methods are employed so that only a limited frequency range is used in some bandpass filtered channel. Passband transmission is utilized in wireless communication and in bandpass filtered channels such as POTS lines. It also allows for frequency-division multiplexing, the digital bit stream is converted first into an equivalent baseband signal, and then to a RF signal. On the receiver side a demodulator is used to detect the signal, a combined equipment for modulation and demodulation is called a modem. In general, there is a relationship between the width of a filters passband and the time required for the filter to respond to new inputs. This is a consequence of the mathematics of Fourier analysis, the limiting frequencies of a passband are defined as those at which the relative intensity or power decreases to a specified fraction of the maximum intensity or power. This decrease in power is often specified to be the half-power points, the difference between the limiting frequencies is called the bandwidth, and is expressed in hertz. The related term bandpass is an adjective that describes a type of filter or filtering process, it is confused with passband. The two words are both words that follow the English rules of formation, the primary meaning is the latter part of the compound

18.
Very-high-bit-rate digital subscriber line
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VDSL offers speeds of up to 52 Mbit/s downstream and 16 Mbit/s upstream, over a single flat untwisted or twisted pair of copper wires using the frequency band from 25 kHz to 12 MHz. These rates mean that VDSL is capable of supporting applications such as television, as well as telephone services and general Internet access. VDSL is deployed over existing wiring used for telephone service. This standard was approved by the International Telecommunication Union in November 2001, second-generation systems use frequencies of up to 30 MHz to provide data rates exceeding 100 Mbit/s simultaneously in both the upstream and downstream directions. The maximum available bit rate is achieved at a range of about 300 meters, the concept of VDSL was first published in 1991 through a joint Bellcore-Stanford research study. The study searched for potential successors to the then-prevalent HDSL and relatively new ADSL, specifically, it explored the feasibility of symmetric and asymmetric data rates exceeding 10 Mbit/s on short phone lines. VDSL2 standard is an enhancement to ITU T G.993.1 that supports asymmetric and symmetric transmission at a net data rate up to 400 Mbit/s on twisted pairs using a bandwidth up to 35 MHz. A VDSL connection uses up to seven frequency bands, so one can allocate the data rate between upstream and downstream differently depending on the offering and spectrum regulations. First generation VDSL standard specified both quadrature amplitude modulation and discrete multi-tone modulation, in 2006, ITU-T standardized VDSL in recommendation G.993.2 which specified only DMT modulation for VDSL2. VDSL2 is an enhancement to VDSL, the protocol is standardized in the International Telecommunication Union telecommunications sector as Recommendation G.993.2. It was announced as finalized on 27 May 2005, and first published on 17 February 2006, several corrections and amendments were published from 2007 to 2011. VDSL2 permits the transmission of asymmetric and symmetric aggregate data rates up to 300+ Mbit/s downstream and upstream on twisted pairs using a bandwidth up to 35 MHz. It deteriorates quickly from a maximum of 350 Mbit/s at source to 100 Mbit/s at 0.5 km and 50 Mbit/s at 1 km, but degrades at a much slower rate from there. Starting from 1.6 km its performance is equal to ADSL2+, aDSL-like long-reach performance is one of the key advantages of VDSL2. LR-VDSL2 enabled systems are capable of supporting speeds of around 1–4 Mbit/s over distances of 4–5 km and this means that VDSL2-based systems, unlike VDSL systems, are not limited to short local loops or MTU/MDUs only, but can also be used for medium range applications. Bonding may be used to combine multiple wire pairs to increase available capacity, Vplus is a technology to achieve higher speeds over existing VDSL2 networks. It was developed by Alcatel-Lucent and standardised in November 2015 in ITU G.993.2 Amendment 1 as VDSL2 profile 35b and it promises to deliver speeds of up to 300 Mbit/s downstream and 100 Mbit/s upstream on loops shorter than 250 m. On longer loops, Vplus falls back to VDSL2 17a vectoring performance, Vplus uses the same tone spacing as VDSL2 17a to allow vectoring across Vplus and 17a lines, and thus mixed deployments and a smooth introduction of Vplus

19.
Cisco Systems
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Through its numerous acquired subsidiaries, such as OpenDNS, WebEx, and Jasper, Cisco specializes into specific tech markets, such as Internet of Things, domain security, and energy management. Cisco is the largest networking company in the world, the stock was added to the Dow Jones Industrial Average on June 8,2009, and is also included in the S&P500 Index, the Russell 1000 Index, NASDAQ-100 Index and the Russell 1000 Growth Stock Index. By the time the company went public in 1990, when it was listed on the NASDAQ, Cisco was the most valuable company in the world by 2000, with a more than $500 billion market capitalization. Despite founding Cisco in 1984, Bosack, along with Kirk Lougheed, continued to work at Stanford on Ciscos first product and it consisted of exact replicas of Stanfords Blue Box router and a stolen copy of the Universitys multiple-protocol router software. The software was written some years earlier at Stanford medical school by research engineer William Yeager. Bosack and Lougheed adapted it into what became the foundation for Cisco IOS, in 1987, Stanford licensed the router software and two computer boards to Cisco. In addition to Bosack, Lerner and Lougheed, Greg Satz, a programmer, and Richard Troiano, the companys first CEO was Bill Graves, who held the position from 1987 to 1988. In 1988, John Morgridge was appointed CEO, the name Cisco was derived from the city name San Francisco, which is why the companys engineers insisted on using the lower case cisco in its early years. The logo is intended to depict the two towers of the Golden Gate Bridge, on February 16,1990, Cisco Systems went public and was listed on the NASDAQ stock exchange. On August 28,1990, Lerner was fired, upon hearing the news, her husband Bosack resigned in protest. The couple walked away from Cisco with $170 million, 70% of which was committed to their own charity, although Cisco was not the first company to develop and sell dedicated network nodes, it was one of the first to sell commercially successful routers supporting multiple network protocols. Classical, CPU-based architecture of early Cisco devices coupled with flexibility of operating system IOS allowed for keeping up with evolving technology needs by means of frequent software upgrades, some popular models of that time managed to stay in production for almost a decade virtually unchanged—a rarity in high-tech industry. This philosophy dominated the companys product lines throughout the 1990s, in 1995, John Morgridge was succeeded by John Chambers. The phenomenal growth of the Internet in mid-to-late 1990s quickly changed the telecom landspe, as the Internet Protocol became widely adopted, the importance of multi-protocol routing declined. In late March 2000, at the height of the bubble, Cisco became the most valuable company in the world. In July 2014, with a cap of about US$129 billion. One of them, Juniper Networks, shipped their first product in 1999, Cisco answered the challenge with homegrown ASICs and fast processing cards for GSR routers and Catalyst 6500 switches. In 2004, Cisco also started migration to new high-end hardware CRS-1, as part of a massive rebranding campaign in 2006, Cisco Systems adopted the shortened name Cisco and created The Human Network advertising campaign

20.
Ethernet in the First Mile Alliance
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The MEF, founded in 2001 as the Metro Ethernet Forum, is a nonprofit international industry consortium, dedicated to adoption of Carrier Ethernet networks and services. The forum is composed of service providers, incumbent local exchange carriers, network equipment vendors and it had 217 members as of September 2015. The MEF is a combination of a technical and a forum to promote the adoption of Metro Ethernet. This contrasts with standard bodies such as the Internet Engineering Task Force, the forum makes recommendations to existing standards bodies and creates specifications that are not being developed by other standards bodies. The MEF was preceded by the Ethernet in the First Mile Alliance and it was established in 2001 to promote standards-based Ethernet in the First Mile technologies and products and position EFM as a networking technology for an access network. In 2005, with the completion of the 802. 3ah standard by the IEEE, in 2015, the MEF voted to change its official legal name to MEF Forum to reflect its expansion in setting standards for virtualized networks. These white papers provide a technical overview of Ethernet services

21.
Metro Ethernet Forum
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The MEF, founded in 2001 as the Metro Ethernet Forum, is a nonprofit international industry consortium, dedicated to adoption of Carrier Ethernet networks and services. The forum is composed of service providers, incumbent local exchange carriers, network equipment vendors and it had 217 members as of September 2015. The MEF is a combination of a technical and a forum to promote the adoption of Metro Ethernet. This contrasts with standard bodies such as the Internet Engineering Task Force, the forum makes recommendations to existing standards bodies and creates specifications that are not being developed by other standards bodies. The MEF was preceded by the Ethernet in the First Mile Alliance and it was established in 2001 to promote standards-based Ethernet in the First Mile technologies and products and position EFM as a networking technology for an access network. In 2005, with the completion of the 802. 3ah standard by the IEEE, in 2015, the MEF voted to change its official legal name to MEF Forum to reflect its expansion in setting standards for virtualized networks. These white papers provide a technical overview of Ethernet services

22.
Ethernet physical layer
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The Ethernet physical layer evolved over a considerable time span and encompasses quite a few physical media interfaces and several magnitudes of speed. The speed ranges from 1 Mbit/s to 100 Gbit/s, while the medium can range from bulky coaxial cable to twisted pair. In general, network protocol stack software will work similarly on all physical layers,10 Gigabit Ethernet was already used in both enterprise and carrier networks by 2007, with 40 Gbit/s and 100 Gigabit Ethernet ratified. Robert Metcalfe, one of the co-inventors of Ethernet, in 2008 said he believed commercial applications using Terabit Ethernet may occur by 2015, though it might require new Ethernet standards. Many Ethernet adapters and switch ports support multiple speeds, using autonegotiation to set the speed, while this can practically be taken for granted for ports supporting twisted-pair cabling, only few optical-fiber ports support multiple speeds. If auto-negotiation fails, some multiple-speed devices sense the speed used by their partner, a 10/100 Ethernet port supports 10BASE-T and 100BASE-TX. A 10/100/1000 Ethernet port supports 10BASE-T, 100BASE-TX, and 1000BASE-T, generally, layers are named by their specifications,10,100,1000, 10G. – the nominal, usable speed for the MAC layer, encoded PHY sublayers usually run higher bitrates BASE, BROAD, PASS – indicates baseband, broadband, or passband signaling -T, -S, -L, -C, -K. g. X for 8b/10b block encoding, R for large blocks 1,2,4,10 – number of lanes used per link or reach for WAN PHYs For 10 Mbit/s, most twisted pair layers use unique encoding, so most often just -T is used. The following sections provide a summary of official Ethernet media types. In addition to official standards, many vendors have implemented proprietary media types for various reasons—often to support longer distances over fiber optic cabling. Early Ethernet standards used Manchester coding so that the signal was self-clocking, all Fast Ethernet variants use a star topology. All Gigabit Ethernet variants use a star topology, initially, half-duplex mode was included in the standard but has been abandoned since. Very few devices support gigabit speed in half-duplex,2. 5GBASE-T and 5GBASE-T are scaled-down variants of 10GBASE-T. These physical layers support twisted pair copper cabling only,10 Gigabit Ethernet defines a version of Ethernet with a nominal data rate of 10 Gbit/s, ten times as fast as Gigabit Ethernet. In 2002, the first 10 Gigabit Ethernet standard was published as IEEE Std 802. 3ae-2002, subsequent standards encompass media types for single-mode fibre, multi-mode fibre, copper backplane and copper twisted pair. All 10-gigabit standards were consolidated into IEEE Std 802. 3-2008, as of 2009,10 Gigabit Ethernet is predominantly deployed in carrier networks, where 10GBASE-LR and 10GBASE-ER enjoy significant market shares. Single-lane 25-gigabit Ethernet is based on one 25.78125 GBd lane of the four from the 100 Gigabit Ethernet standard developed by task force P802. 3by, 25GBASE-T over twisted pair was approved alongside 40GBASE-T within IEEE802. 3bq

23.
Optical fiber
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An optical fiber or optical fibre is a flexible, transparent fiber made by drawing glass or plastic to a diameter slightly thicker than that of a human hair. Fibers are also used for illumination, and are wrapped in bundles so that they may be used to carry images, thus allowing viewing in confined spaces, as in the case of a fiberscope. Specially designed fibers are used for a variety of other applications, some of them being fiber optic sensors. Optical fibers typically include a transparent core surrounded by a transparent cladding material with an index of refraction. Light is kept in the core by the phenomenon of internal reflection which causes the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are called multi-mode fibers, multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,000 meters, being able to join optical fibers with low loss is important in fiber optic communication. This is more complex than joining electrical wire or cable and involves careful cleaving of the fibers, precise alignment of the cores. For applications that demand a permanent connection a fusion splice is common, in this technique, an electric arc is used to melt the ends of the fibers together. Another common technique is a splice, where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made by means of specialized optical fiber connectors, the field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. The term was coined by Indian physicist Narinder Singh Kapany who is acknowledged as the father of fiber optics. Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by Daniel Colladon, John Tyndall included a demonstration of it in his public lectures in London,12 years later. When the ray passes from water to air it is bent from the perpendicular. If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the angle which marks the limit where total reflection begins is called the limiting angle of the medium. For water this angle is 48°27′, for flint glass it is 38°41′, unpigmented human hairs have also been shown to act as an optical fiber. Practical applications, such as close internal illumination during dentistry, appeared early in the twentieth century, image transmission through tubes was demonstrated independently by the radio experimenter Clarence Hansell and the television pioneer John Logie Baird in the 1920s. The principle was first used for medical examinations by Heinrich Lamm in the following decade

24.
Point-to-multipoint communication
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Point-to-multipoint is often abbreviated as P2MP, PTMP, or PMP. Point-to-multipoint telecommunications is most typically used in wireless Internet and IP telephony via gigahertz radio frequencies, P2MP systems have been designed both as single and bi-directional systems. A central antenna or antenna array broadcasts to several receiving antennas, Point to Multipoint is the most popular approach for wireless communications that have a large number of nodes, end destinations or end users. Point to Multipoint generally assumes there is a central Base Station to which remote Subscriber Units or Customer Premises Equipment, connections between the Base Station and Subscriber Units can be either Line of Sight or for lower-frequency radio systems Non-Line-of-Sight where link budgets permit. Generally, lower frequencies can offer non-Line-of Sight connections, various software planning tools can be used to determine feasibility of potential connections using topographic data as well as link budget simulation. Often the point to multipoint links are installed to reduce the cost of infrastructure and increase the number of CPEs, Point to Multipoint wireless networks employing directional antennas are affected by the hidden node problem in case they employ a CSMA/CA medium access control protocol. The negative impact of the hidden node problem can be mitigated using a TDMA based protocol or a polling protocol rather than the CSMA/CA protocol, the telecommunications signal in a Point to Multipoint system is typically bi-directional, either time division multiple access or channelized. Systems using Frequency Division Duplexing offer full duplex connections between base station and remote sites, and Time Division Duplex systems offer half duplex connections, Point to Multipoint systems can be implemented in Licensed, Semi-licensed or Unlicensed frequency bands depending on the specific application. The Base Station may have a single Omnidirectional antenna or multiple Sector Antennas which is used to increase both range and capacity. All-to-all communication Multipoint microwave distribution system Point-to-point Wireless Communications Wireless Access Point List of emerging technologies Backhaul

25.
Twisted pair
–
It was invented by Alexander Graham Bell. In balanced pair operation, the two wires carry equal and opposite signals, and the destination detects the difference between the two and this is known as differential mode transmission. Noise sources introduce signals into the wires by coupling of electric or magnetic fields, the noise thus produces a common-mode signal which is canceled at the receiver when the difference signal is taken. This problem is especially apparent in telecommunication cables where pairs in the same cable lie next to each other for many miles, one pair can induce crosstalk in another and it is additive along the length of the cable. Twisting the pairs counters this effect as on each half twist the wire nearest to the noise-source is exchanged, providing the interfering source remains uniform, or nearly so, over the distance of a single twist, the induced noise will remain common-mode. Differential signaling also reduces electromagnetic radiation from the cable, along with the associated attenuation allowing for greater distance between exchanges, the twist rate makes up part of the specification for a given type of cable. When nearby pairs have equal twist rates, the conductors of the different pairs may repeatedly lie next to each other. For this reason it is specified that, at least for cables containing small numbers of pairs. In contrast to shielded or foiled twisted pair, UTP cable is not surrounded by any shielding, UTP is the primary wire type for telephone usage and is very common for computer networking, especially as patch cables or temporary network connections due to the high flexibility of the cables. The earliest telephones used telegraph lines, or open-wire single-wire earth return circuits, in the 1880s electric trams were installed in many cities, which induced noise into these circuits. Lawsuits being unavailing, the telephone companies converted to balanced circuits, as electrical power distribution became more commonplace, this measure proved inadequate. Two wires, strung on either side of cross bars on utility poles, within a few years, the growing use of electricity again brought an increase of interference, so engineers devised a method called wire transposition, to cancel out the interference. In wire transposition, the wires exchange position once every several poles, in this way, the two wires would receive similar EMI from power lines. This represented an early implementation of twisting, with a twist rate of about four twists per kilometre, such open-wire balanced lines with periodic transpositions still survive today in some rural areas. Twisted-pair cabling was invented by Alexander Graham Bell in 1881, by 1900, the entire American telephone line network was either twisted pair or open wire with transposition to guard against interference. UTP cables are found in many Ethernet networks and telephone systems, for indoor telephone applications, UTP is often grouped into sets of 25 pairs according to a standard 25-pair color code originally developed by AT&T Corporation. A typical subset of these colors shows up in most UTP cables, for urban outdoor telephone cables containing hundreds or thousands of pairs, the cable is divided into small but identical bundles. Each bundle consists of twisted pairs that have different twist rates, the bundles are in turn twisted together to make up the cable

26.
Full-duplex
–
A duplex communication system requires a pair of channels/frequencies hence the term duplex meaning two parts. The two channels are defined as uplink/downlink or reverse/forward, in a full-duplex system simultaneous transmission/reception is available, i. e. One can transmit and receive simultaneously, in a half-duplex system, each party can communicate with the other but not simultaneously, the communication is one direction at a time. Half duplex systems utilize separate channels for uplink and downlink, i. e. a transmit, in a half duplex communications system one user is allowed to transmit on the uplink channel at a time. The transmitted uplink signal is frequency translated via a radio/repeater to the downlink receive frequency which is received by all other radios tuned to the downlink/receive frequency. A half-duplex system is defined as system which operates two, hence duplex, dedicated uplink/downlink channels/frequencies. In a half duplex system a single path is provided for uplink, all uplink messages are broadcast via the downlink channel to all users simultaneously via a repeater which performs uplink to downlink channel/frequency translation. All cellular and land line PSTNs and PDSNs are full duplex systems, all full duplex systems require a channel/frequency translator via a radio/repeater. This is required in order to translate the uplink/transmit transmission from one to the downlink/receive channel/frequency of user two. Full duplex systems are one to one private systems unlike half duplex systems which broadcast to all users and this effectively makes the cable itself a collision-free environment and doubles the maximum total transmission capacity supported by each Ethernet connection. Time-division duplexing is commonly referred to as simplex communications, a single channel/frequency is employed for bidirectional communications. The term simplex communication as applied to TDM single channel systems predates the term TDD by at least 80 years, frequency-division duplexing as with any other duplex system is defined by two channel/frequency simultaneous communication. A channel/frequency pair are assigned to individual user on the system. An FDD system requires frequency translation from user 1 uplink/reverse frequency to user 2 downlink/forward frequency, full-duplex audio systems like telephones can create echo, which needs to be removed. Echo occurs when the coming out of the speaker, originating from the far end. The sound then reappears at the source end, but delayed. This feedback path may be acoustic, through the air, or it may be mechanically coupled, echo cancellation is a signal-processing operation that subtracts the far-end signal from the microphone signal before it is sent back over the network. Echo cancellation is important to the V.32, V.34, V.56, echo cancelers are available as both software and hardware implementations

27.
Point-to-point (telecommunications)
–
In telecommunications, a point-to-point connection refers to a communications connection between two nodes or endpoints. An example is a call, in which one telephone is connected with one other. This is contrasted with a point-to-multipoint or broadcast connection, in which many nodes can receive information transmitted by one node, other examples of point-to-point communications links are leased lines, microwave relay links, and two way radio. Point-to-point is sometimes abbreviated as P2P and this usage of P2P is distinct from P2P referring to peer-to-peer for file sharing networks. A traditional point-to-point data link is a medium with exactly two endpoints and no data or packet formatting. The host computers at either end had to take responsibility for formatting the data transmitted between them. The connection between the computer and the medium was generally implemented through an RS-232 or similar interface. Computers in close proximity may be connected by wires directly between their interface cards, when connected at a distance, each endpoint would be fitted with a modem to convert analog telecommunications signals into a digital data stream. When the connection used a telecommunications provider, the connections were called a dedicated, leased, the ARPANET used leased lines to provide point-to-point data links between its packet-switching nodes, which were called Interface Message Processors. In, the term point-to-point telecommunications relates to fixed wireless communications for Internet or voice over IP via radio frequencies in the multi-gigahertz range. The Telecommunications Industry Associations engineering committees develop U. S. standards for point-to-point communications, online tools help users find if they have such line of sight. The telecommunications signal is typically bi-directional, either time division multiple access or channelized, in hubs and switches, a hub provides a point-to-multipoint circuit which divides the total bandwidth supplied by the hub among each connected client node. Within many switched telecommunications systems, it is possible to establish a permanent circuit, one example might be a telephone in the lobby of a public building, which is programmed to ring only the number of a telephone dispatcher. Nailing down a switched connection saves the cost of running a circuit between the two points. The resources in such a connection can be released when no longer needed, for example, a television circuit from a parade route back to the studio

28.
ITU G.993.1
–
VDSL offers speeds of up to 52 Mbit/s downstream and 16 Mbit/s upstream, over a single flat untwisted or twisted pair of copper wires using the frequency band from 25 kHz to 12 MHz. These rates mean that VDSL is capable of supporting applications such as television, as well as telephone services and general Internet access. VDSL is deployed over existing wiring used for telephone service. This standard was approved by the International Telecommunication Union in November 2001, second-generation systems use frequencies of up to 30 MHz to provide data rates exceeding 100 Mbit/s simultaneously in both the upstream and downstream directions. The maximum available bit rate is achieved at a range of about 300 meters, the concept of VDSL was first published in 1991 through a joint Bellcore-Stanford research study. The study searched for potential successors to the then-prevalent HDSL and relatively new ADSL, specifically, it explored the feasibility of symmetric and asymmetric data rates exceeding 10 Mbit/s on short phone lines. VDSL2 standard is an enhancement to ITU T G.993.1 that supports asymmetric and symmetric transmission at a net data rate up to 400 Mbit/s on twisted pairs using a bandwidth up to 35 MHz. A VDSL connection uses up to seven frequency bands, so one can allocate the data rate between upstream and downstream differently depending on the offering and spectrum regulations. First generation VDSL standard specified both quadrature amplitude modulation and discrete multi-tone modulation, in 2006, ITU-T standardized VDSL in recommendation G.993.2 which specified only DMT modulation for VDSL2. VDSL2 is an enhancement to VDSL, the protocol is standardized in the International Telecommunication Union telecommunications sector as Recommendation G.993.2. It was announced as finalized on 27 May 2005, and first published on 17 February 2006, several corrections and amendments were published from 2007 to 2011. VDSL2 permits the transmission of asymmetric and symmetric aggregate data rates up to 300+ Mbit/s downstream and upstream on twisted pairs using a bandwidth up to 35 MHz. It deteriorates quickly from a maximum of 350 Mbit/s at source to 100 Mbit/s at 0.5 km and 50 Mbit/s at 1 km, but degrades at a much slower rate from there. Starting from 1.6 km its performance is equal to ADSL2+, aDSL-like long-reach performance is one of the key advantages of VDSL2. LR-VDSL2 enabled systems are capable of supporting speeds of around 1–4 Mbit/s over distances of 4–5 km and this means that VDSL2-based systems, unlike VDSL systems, are not limited to short local loops or MTU/MDUs only, but can also be used for medium range applications. Bonding may be used to combine multiple wire pairs to increase available capacity, Vplus is a technology to achieve higher speeds over existing VDSL2 networks. It was developed by Alcatel-Lucent and standardised in November 2015 in ITU G.993.2 Amendment 1 as VDSL2 profile 35b and it promises to deliver speeds of up to 300 Mbit/s downstream and 100 Mbit/s upstream on loops shorter than 250 m. On longer loops, Vplus falls back to VDSL2 17a vectoring performance, Vplus uses the same tone spacing as VDSL2 17a to allow vectoring across Vplus and 17a lines, and thus mixed deployments and a smooth introduction of Vplus

29.
VDSL
–
VDSL offers speeds of up to 52 Mbit/s downstream and 16 Mbit/s upstream, over a single flat untwisted or twisted pair of copper wires using the frequency band from 25 kHz to 12 MHz. These rates mean that VDSL is capable of supporting applications such as television, as well as telephone services and general Internet access. VDSL is deployed over existing wiring used for telephone service. This standard was approved by the International Telecommunication Union in November 2001, second-generation systems use frequencies of up to 30 MHz to provide data rates exceeding 100 Mbit/s simultaneously in both the upstream and downstream directions. The maximum available bit rate is achieved at a range of about 300 meters, the concept of VDSL was first published in 1991 through a joint Bellcore-Stanford research study. The study searched for potential successors to the then-prevalent HDSL and relatively new ADSL, specifically, it explored the feasibility of symmetric and asymmetric data rates exceeding 10 Mbit/s on short phone lines. VDSL2 standard is an enhancement to ITU T G.993.1 that supports asymmetric and symmetric transmission at a net data rate up to 400 Mbit/s on twisted pairs using a bandwidth up to 35 MHz. A VDSL connection uses up to seven frequency bands, so one can allocate the data rate between upstream and downstream differently depending on the offering and spectrum regulations. First generation VDSL standard specified both quadrature amplitude modulation and discrete multi-tone modulation, in 2006, ITU-T standardized VDSL in recommendation G.993.2 which specified only DMT modulation for VDSL2. VDSL2 is an enhancement to VDSL, the protocol is standardized in the International Telecommunication Union telecommunications sector as Recommendation G.993.2. It was announced as finalized on 27 May 2005, and first published on 17 February 2006, several corrections and amendments were published from 2007 to 2011. VDSL2 permits the transmission of asymmetric and symmetric aggregate data rates up to 300+ Mbit/s downstream and upstream on twisted pairs using a bandwidth up to 35 MHz. It deteriorates quickly from a maximum of 350 Mbit/s at source to 100 Mbit/s at 0.5 km and 50 Mbit/s at 1 km, but degrades at a much slower rate from there. Starting from 1.6 km its performance is equal to ADSL2+, aDSL-like long-reach performance is one of the key advantages of VDSL2. LR-VDSL2 enabled systems are capable of supporting speeds of around 1–4 Mbit/s over distances of 4–5 km and this means that VDSL2-based systems, unlike VDSL systems, are not limited to short local loops or MTU/MDUs only, but can also be used for medium range applications. Bonding may be used to combine multiple wire pairs to increase available capacity, Vplus is a technology to achieve higher speeds over existing VDSL2 networks. It was developed by Alcatel-Lucent and standardised in November 2015 in ITU G.993.2 Amendment 1 as VDSL2 profile 35b and it promises to deliver speeds of up to 300 Mbit/s downstream and 100 Mbit/s upstream on loops shorter than 250 m. On longer loops, Vplus falls back to VDSL2 17a vectoring performance, Vplus uses the same tone spacing as VDSL2 17a to allow vectoring across Vplus and 17a lines, and thus mixed deployments and a smooth introduction of Vplus

30.
100BASE-LX10
–
In computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s. Of the Fast Ethernet standards, 100BASE-TX is by far the most common, Fast Ethernet was introduced in 1995 as the IEEE802. 3u standard and remained the fastest version of Ethernet for three years before the introduction of Gigabit Ethernet. The acronym GE/FE is sometimes used for supporting both standards. Fast Ethernet is an extension of the 10-megabit Ethernet standard and it runs on UTP data or optical fiber cable in a star wired bus topology, similar to 10BASE-T where all cables are attached to a hub. Fast Ethernet devices are backward compatible with existing 10BASE-T systems. Fast Ethernet is sometimes referred to as 100BASE-X, where X is a placeholder for the FX, the standard specifies the use of CSMA/CD for media access control. A full-duplex mode is also specified and in all modern networks use Ethernet switches. The 100 in the type designation refers to the transmission speed of 100 Mbit/s. The letter following the dash refers to the medium that carries the signal. A Fast Ethernet adapter can be divided into a media access controller, which deals with the higher-level issues of medium availability. The MAC may be linked to the PHY by a four-bit 25 MHz synchronous parallel interface known as a media-independent interface, in rare cases the MII may be an external connection but is usually a connection between ICs in a network adapter or even within a single IC. The specs are based on the assumption that the interface between MAC and PHY will be a MII but they do not require it. Repeaters may use the MII to connect to multiple PHYs for their different interfaces, the MII fixes the theoretical maximum data bit rate for all versions of Fast Ethernet to 100 Mbit/s. 100BASE-T is any of several Fast Ethernet standards for twisted pair cables, including, 100BASE-TX, 100BASE-T4, the segment length for a 100BASE-T cable is limited to 100 metres. All are or were standards under IEEE802.3, almost all 100BASE-T installations are 100BASE-TX. In the early days of Fast Ethernet, much vendor advertising centered on claims by competing standards that said vendors standards will work better with existing cables than other standards. Thus most networks had to be rewired for 100 Megabit speed whether or not there had supposedly been CAT3 or CAT5 cable runs, 100BASE-TX is the predominant form of Fast Ethernet, and runs over two wire-pairs inside a category 5 or above cable. Like 10BASE-T, the pairs in a standard connection are terminated on pins 1,2,3 and 6

31.
100BASE-BX
–
In computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s. Of the Fast Ethernet standards, 100BASE-TX is by far the most common, Fast Ethernet was introduced in 1995 as the IEEE802. 3u standard and remained the fastest version of Ethernet for three years before the introduction of Gigabit Ethernet. The acronym GE/FE is sometimes used for supporting both standards. Fast Ethernet is an extension of the 10-megabit Ethernet standard and it runs on UTP data or optical fiber cable in a star wired bus topology, similar to 10BASE-T where all cables are attached to a hub. Fast Ethernet devices are backward compatible with existing 10BASE-T systems. Fast Ethernet is sometimes referred to as 100BASE-X, where X is a placeholder for the FX, the standard specifies the use of CSMA/CD for media access control. A full-duplex mode is also specified and in all modern networks use Ethernet switches. The 100 in the type designation refers to the transmission speed of 100 Mbit/s. The letter following the dash refers to the medium that carries the signal. A Fast Ethernet adapter can be divided into a media access controller, which deals with the higher-level issues of medium availability. The MAC may be linked to the PHY by a four-bit 25 MHz synchronous parallel interface known as a media-independent interface, in rare cases the MII may be an external connection but is usually a connection between ICs in a network adapter or even within a single IC. The specs are based on the assumption that the interface between MAC and PHY will be a MII but they do not require it. Repeaters may use the MII to connect to multiple PHYs for their different interfaces, the MII fixes the theoretical maximum data bit rate for all versions of Fast Ethernet to 100 Mbit/s. 100BASE-T is any of several Fast Ethernet standards for twisted pair cables, including, 100BASE-TX, 100BASE-T4, the segment length for a 100BASE-T cable is limited to 100 metres. All are or were standards under IEEE802.3, almost all 100BASE-T installations are 100BASE-TX. In the early days of Fast Ethernet, much vendor advertising centered on claims by competing standards that said vendors standards will work better with existing cables than other standards. Thus most networks had to be rewired for 100 Megabit speed whether or not there had supposedly been CAT3 or CAT5 cable runs, 100BASE-TX is the predominant form of Fast Ethernet, and runs over two wire-pairs inside a category 5 or above cable. Like 10BASE-T, the pairs in a standard connection are terminated on pins 1,2,3 and 6

Ethernet
–
Ethernet /ˈiːθərnɛt/ is a family of computer networking technologies commonly used in local area networks, metropolitan area networks and wide area networks. It was commercially introduced in 1980 and first standardized in 1983 as IEEE802.3, over time, Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI and ARCNE

Computer network
–
A computer network or data network is a telecommunications network which allows nodes to share resources. In computer networks, networked computing devices exchange data with other using a data link. The connections between nodes are established using either cable media or wireless media, the best-known computer network is the Internet. Network com

2.
Fiber optic cables are used to transmit light from one computer/network node to another

3.
Computers are very often connected to networks using wireless links

4.
An ATM network interface in the form of an accessory card. A lot of network interfaces are built-in.

Access network
–
An access network is a type of telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the network, which connects local providers to each other. The access network may be divided between feeder plant or distribution network, and drop plant or edge network. An access network or outside plant

1.
Access Network Authentication High-Level Example

Last mile
–
More specifically, the last mile refers to the portion of the telecommunications network chain that physically reaches the end-users premises. The word mile is used metaphorically, the length of the last mile link may be more or less than a mile. Because the last mile of a network to the user is conversely the first mile from the premises to the ou

1.
This article is about telecommunications terminology. For the use of the term "last mile" in relation to transportation, see Last mile (transportation).

Institute of Electrical and Electronics Engineers
–
The Institute of Electrical and Electronics Engineers is a professional association with its corporate office in New York City and its operations center in Piscataway, New Jersey. It was formed in 1963 from the amalgamation of the American Institute of Electrical Engineers, today, it is the worlds largest association of technical professionals with

1.
The IEEE corporate office is on the 17th floor of 3 Park Avenue in New York City

Passive optical network
–
A PON consists of an optical line terminal at the service providers central office and a number of optical network units or optical network terminals, near end users. A PON reduces the amount of fiber and central office equipment required compared with point-to-point architectures, a passive optical network is a form of fiber-optic access network.

1.
Downstream traffic in active (top) vs. passive optical network

Wide area network
–
A wide area network is a telecommunications network or computer network that extends over a large geographical distance. Wide area networks are often established with leased telecommunication circuits, business, education and government entities use wide area networks to relay data among staff, students, clients, buyers, and suppliers from various

1.
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (July 2015)

Local area network
–
By contrast, a wide area network, not only covers a larger geographic distance, but also generally involves leased telecommunication circuits or Internet links. An even greater contrast is the Internet, which is a system of globally connected business, Ethernet and Wi-Fi are the two most common transmission technologies in use for local area networ

1.
A conceptual diagram of a local area network using 10BASE5 Ethernet

Asynchronous Transfer Mode
–
ATM was developed to meet the needs of the Broadband Integrated Services Digital Network, as defined in the late 1980s, and designed to unify telecommunication and computer networks. It was designed for a network that must handle both traditional high-throughput data traffic, and real-time, low-latency content such as voice and video. The reference

1.
IBM Turboways ATM 155 PCI network interface card

2.
Marconi ForeRunnerLE 25 ATM PCI network interface card

Nortel
–
It was founded in Montreal, Quebec in 1895 as the Northern Electric and Manufacturing Company. At its height, Nortel accounted for more than a third of the valuation of all the companies listed on the Toronto Stock Exchange. Nortel had filed for protection from its creditors in the United States, Canada, in June 2009, the company announced it would

1.
An audio amplifier manufactured by Northern Electric.

2.
1950 Logo

3.
Nortel's former head offices at 195 The West Mall

4.
Former campus in California

Digital Subscriber Line
–
Digital subscriber line is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line, DSL service can be delivered simultaneously with wired telephone service on the same telephone line. This is possible because

1.
A DSL modem

2.
DSL SoC

3.
Example of a DSLAM from 2006

Half-duplex
–
A duplex communication system requires a pair of channels/frequencies hence the term duplex meaning two parts. The two channels are defined as uplink/downlink or reverse/forward, in a full-duplex system simultaneous transmission/reception is available, i. e. One can transmit and receive simultaneously, in a half-duplex system, each party can commun

1.
A simple illustration of a half-duplex communication system

2.
A simple illustration of a full-duplex communication system. Full-duplex is not common in handheld radios as shown here due to the cost and complexity of common duplexing methods, but is used in telephones, cellphones and cordless phones.

Fiber optic communication
–
Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms a carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, optical fiber is used by many telecommunications compan

2.
A GBIC module (shown here with its cover removed), is an optical and electrical transceiver. The electrical connector is at top right, and the optical connectors are at bottom left

3.
A cable reel trailer with conduit that can carry optical fiber

4.
Multi-mode optical fiber in an underground service pit

Fiber to the home
–
Fiber to the x is a generic term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile telecommunications. As fiber optic cables are able to much more data than copper cables, especially over long distances. FTTX is a generalization for several configurations of fibre deployment, arra

1.
The inside of a fiber cabinet. The left-hand side contains the fiber, and the right-hand side contains the copper.

2.
A schematic illustrating how FTTX architectures vary with regard to the distance between the optical fiber and the end user. The building on the left is the central office; the building on the right is one of the buildings served by the central office. Dotted rectangles represent separate living or office spaces within the same building.

Infineon Technologies
–
As of 30 September 2016, Infineon had 36,299 employees worldwide. In fiscal year 2016, the company achieved sales of €6.473 billion, on 1 May 2006, Infineons Memory Products division was carved out as a distinct company called Qimonda AG, which at its height employed about 13,500 people worldwide. Qimonda was listed on the New York Stock Exchange u

1.
Infineon Technologies AG

Baseband
–
Baseband is a signal that has a very narrow and near-zero frequency range, i. e. a spectral magnitude that is nonzero only for frequencies in the vicinity of the origin and negligible elsewhere. In telecommunications and signal processing, baseband signals are transmitted without modulation, baseband has a low-frequency—contained within the bandwid

1.
Spectrum of a baseband signal, energy E per unit frequency as a function of frequency f. The total energy is the area under the line.

Passband
–
A passband is the range of frequencies or wavelengths that can pass through a filter. For example, a radio receiver contains a filter to select the frequency of the desired radio signal out of all the radio waves picked up by its antenna. The passband of a receiver is the range of frequencies it can receive, a bandpass-filtered signal, is known as

Very-high-bit-rate digital subscriber line
–
VDSL offers speeds of up to 52 Mbit/s downstream and 16 Mbit/s upstream, over a single flat untwisted or twisted pair of copper wires using the frequency band from 25 kHz to 12 MHz. These rates mean that VDSL is capable of supporting applications such as television, as well as telephone services and general Internet access. VDSL is deployed over ex

1.
This VDSL modem used in Taiwan provides 4 Ethernet ports and an internal filter for voice-data separation.

Cisco Systems
–
Through its numerous acquired subsidiaries, such as OpenDNS, WebEx, and Jasper, Cisco specializes into specific tech markets, such as Internet of Things, domain security, and energy management. Cisco is the largest networking company in the world, the stock was added to the Dow Jones Industrial Average on June 8,2009, and is also included in the S&

1.
One of the many buildings on the Cisco Systems campus in San Jose

2.
Cisco Systems, Inc.

3.
A Cisco facility in Chennai, India. India is one of the company's largest overseas markets and production centers.

Ethernet in the First Mile Alliance
–
The MEF, founded in 2001 as the Metro Ethernet Forum, is a nonprofit international industry consortium, dedicated to adoption of Carrier Ethernet networks and services. The forum is composed of service providers, incumbent local exchange carriers, network equipment vendors and it had 217 members as of September 2015. The MEF is a combination of a t

1.
Logo of the EFMA

Metro Ethernet Forum
–
The MEF, founded in 2001 as the Metro Ethernet Forum, is a nonprofit international industry consortium, dedicated to adoption of Carrier Ethernet networks and services. The forum is composed of service providers, incumbent local exchange carriers, network equipment vendors and it had 217 members as of September 2015. The MEF is a combination of a t

1.
Logo of the EFMA

Ethernet physical layer
–
The Ethernet physical layer evolved over a considerable time span and encompasses quite a few physical media interfaces and several magnitudes of speed. The speed ranges from 1 Mbit/s to 100 Gbit/s, while the medium can range from bulky coaxial cable to twisted pair. In general, network protocol stack software will work similarly on all physical la

1.
Ethernet physical layer

Optical fiber
–
An optical fiber or optical fibre is a flexible, transparent fiber made by drawing glass or plastic to a diameter slightly thicker than that of a human hair. Fibers are also used for illumination, and are wrapped in bundles so that they may be used to carry images, thus allowing viewing in confined spaces, as in the case of a fiberscope. Specially

1.
A bundle of optical fibers

2.
Fiber crew installing a 432-count fiber cable underneath the streets of Midtown Manhattan, New York City

3.
A TOSLINK fiber optic audio cable with red light being shone in one end transmits the light to the other end

Point-to-multipoint communication
–
Point-to-multipoint is often abbreviated as P2MP, PTMP, or PMP. Point-to-multipoint telecommunications is most typically used in wireless Internet and IP telephony via gigahertz radio frequencies, P2MP systems have been designed both as single and bi-directional systems. A central antenna or antenna array broadcasts to several receiving antennas, P

Twisted pair
–
It was invented by Alexander Graham Bell. In balanced pair operation, the two wires carry equal and opposite signals, and the destination detects the difference between the two and this is known as differential mode transmission. Noise sources introduce signals into the wires by coupling of electric or magnetic fields, the noise thus produces a com

1.
Unshielded twisted pair cable with different twist rates

2.
Wire transposition on top of pole

3.
F/UTP cable

4.
S/FTP cable

Full-duplex
–
A duplex communication system requires a pair of channels/frequencies hence the term duplex meaning two parts. The two channels are defined as uplink/downlink or reverse/forward, in a full-duplex system simultaneous transmission/reception is available, i. e. One can transmit and receive simultaneously, in a half-duplex system, each party can commun

1.
A simple illustration of a half-duplex communication system

2.
A simple illustration of a full-duplex communication system. Full-duplex is not common in handheld radios as shown here due to the cost and complexity of common duplexing methods, but is used in telephones, cellphones and cordless phones.

Point-to-point (telecommunications)
–
In telecommunications, a point-to-point connection refers to a communications connection between two nodes or endpoints. An example is a call, in which one telephone is connected with one other. This is contrasted with a point-to-multipoint or broadcast connection, in which many nodes can receive information transmitted by one node, other examples

ITU G.993.1
–
VDSL offers speeds of up to 52 Mbit/s downstream and 16 Mbit/s upstream, over a single flat untwisted or twisted pair of copper wires using the frequency band from 25 kHz to 12 MHz. These rates mean that VDSL is capable of supporting applications such as television, as well as telephone services and general Internet access. VDSL is deployed over ex

1.
This VDSL modem used in Taiwan provides 4 Ethernet ports and an internal filter for voice-data separation.

VDSL
–
VDSL offers speeds of up to 52 Mbit/s downstream and 16 Mbit/s upstream, over a single flat untwisted or twisted pair of copper wires using the frequency band from 25 kHz to 12 MHz. These rates mean that VDSL is capable of supporting applications such as television, as well as telephone services and general Internet access. VDSL is deployed over ex

1.
This VDSL modem used in Taiwan provides 4 Ethernet ports and an internal filter for voice-data separation.

100BASE-LX10
–
In computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s. Of the Fast Ethernet standards, 100BASE-TX is by far the most common, Fast Ethernet was introduced in 1995 as the IEEE802. 3u standard and remained the fastest version of Ethernet for three years before

1.
Intel PRO/100 Fast Ethernet NIC, a PCI card

2.
3Com 3c905-TX 100BASE-TX PCI network interface card

100BASE-BX
–
In computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s. Of the Fast Ethernet standards, 100BASE-TX is by far the most common, Fast Ethernet was introduced in 1995 as the IEEE802. 3u standard and remained the fastest version of Ethernet for three years before

1.
The inside of a fiber cabinet. The left-hand side contains the fiber, and the right-hand side contains the copper.

2.
A schematic illustrating how FTTX architectures vary with regard to the distance between the optical fiber and the end user. The building on the left is the central office; the building on the right is one of the buildings served by the central office. Dotted rectangles represent separate living or office spaces within the same building.

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CableFree Microwave Backhaul links deployed for mobile operators in the Middle East. These microwave links typically carry a mix of Ethernet /IP, TDM (Nx E1) and SDH traffic to connect the Cellular Base Stations (BTS) to the central sites of the cellular operator. Such microwave links used to carry 2xE1 (4Mbit/s) now carry 400Mbit/s or more, using modern 1024QAM or higher modulation schemes.

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Ethernet Frame. Each lower slot designates an octet. Note it does not show any Virtual LAN tags, which increase the size of the frame by 32-bits per tag. Multiprotocol Label Switching also uses 32-bits per each label (in a stacking arrangement).

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Given a single Power over Ethernet connection (single gray cable looping below), a PoE splitter provides both data (gray cable looping above) and power (black cable also looping above) connections for a wireless access point. The splitter is the silver and black box in the middle, between the wiring box on the left and the access point (with its two antennas) on the right. The PoE connection eliminates the need for a nearby power outlet.